Highly-Efficient Seawater Hydrogen Production via a Plug-and-Play Solar-Powered Membrane Distillation-Electrolysis...

Reliance on fossil fuels and global freshwater scarcity challenge the sustainable production of green hydrogen (H₂). Here, we introduce a plug-and-play solar-powered membrane distillation-electrolysis (SMDE) system for sustainable H₂ production from seawater. The system is readily constructed by simply coupling a photovoltaic (PV) panel, a membrane distillation (MD) module, and a proton-exchange membrane (PEM) electrolyzer. Lab-scale experiments confirm the system's technical viability under varying conditions. Thermodynamic analysis further reveals that waste heat from the PV panel effectively drives the MD process, supplying sufficient freshwater for electrolysis while keeping water consumption below 25% of the produced mass. Compared to existing solar-powered seawater H₂ production technologies, the SMDE system attains a high solar-to-hydrogen conversion efficiency (η_STH) of up to 23% and a low levelized cost of H₂ (LCOH) down to $1.70 per kg, while offering superior technical maturity and operational durability. Moreover, by integrating MD and PEM electrolysis into renewable energy production systems, surplus electricity can be converted into storable H₂, thereby addressing energy overcapacity. Overall, this work demonstrates that the rational integration of mature engineering technologies can overcome the complex challenges at the water-energy nexus.